(A) Wetland conservation act implementation. Carver County adopts and incorporates by reference the Minnesota Wetland Conservation Act and its implementing rules as set forth in Minn. Rules chapter 8420, as amended periodically.
(B) Transition setbacks for surface water protection.
(1) Requirement. Establishment or preservation of an unmanicured, vegetated, transition setback adjacent and contiguous to wetlands, lakes, streams, rivers, and public and private ditches is required for projects meeting the thresholds described in § 153.43. For projects where the construction activity does not occupy the full parcel, the requirement for setbacks applies only to the portion of the parcel where construction activity is taking place.
(2) Exempt activities. Activities meeting the exemption requirements of Minn. Rule 8420 are exempt from these requirements. Wetlands or portions of wetlands impacted and mitigated through Minn. Rule 8420 are exempt from these setback requirements.
(3) Determining setback widths.
(a) Reference point. The setback width will be measured from:
1. The delineated wetland edge for wetlands; For wetlands without an approved wetland boundary and type, the wetland boundary shall be determined based on aerial review. NWI mapping may be used if aerial photography is not available.
2. The top of bank for streams and rivers.
3. The ordinary high-water level (OHWL) for lakes; for lakes without an approved OHWL, the water's edge as determined based on aerial review shall be used.
(b) Base width. The base width for a transition setback is 20 feet for wetlands and 30 feet for lakes and streams.
(c) Minimum width. The minimum width for a transition setback is:
1. Thirty feet for lakes, and streams.
2. Thirty feet for wetlands that receive a ranking of "high" value in the Carver County Wetland Function and Value Assessment or an equivalent wetland function and value assessment.
3. Twenty feet for wetlands, except for "high" value wetlands.
(d) Applied width. The setback width shall be adjusted to reflect site conditions based on the criteria below. The maximum applied width is 50 feet.
1. Stormwater treatment. The base width must be increased by ten feet in areas where untreated stormwater runoff from impervious surfaces is directed to the surface water and not stormwater BMPs.
2. Slopes. For every 5% increase in average setback slope from 5%, the base width must be increased five feet in the area where the slope increase exists.
Average Setback Slope
|
Increase in Setback Width
|
0-5% slope | No increase |
5-10% slope | Add 5 feet to base width |
10-15% slope | Add 10 feet to base width |
>15% slope | Add 15 feet to base width |
(e) Flexibility in applied width. The county retains the right to allow the setback width to vary and the minimum width to be reduced based on demonstrated site constraints, to allow unique BMPs, or to allow other activities that protect and enhance the surface water resource. Adjustments to the applied width may not result in a reduction to the total setback area and the adjusted setback must provide surface water protection at least equivalent to a setback of uniform width (e.g., the setback area may be reduced in one area adjacent to the surface water if the area is replaced at a one-to-one ratio elsewhere around the same resource).
(f) Subject to county approval, the total setback area may be reduced if the area is replaced at a two-to-one ratio around another surface water of comparable value on site.
(g) Linear projects. For linear projects, non-impervious portions of the right of way are allowed within the setback.
(h) Access. In situations where the setback is entirely on private property, limited clearing and trimming of trees, shrubs, and other vegetation within the setback is allowed to create an access path to the waters edge. The path shall not exceed 12 feet in width.
(4) Setback vegetation requirements.
(a) Setback vegetation shall not be cultivated, cropped, pastured, mowed, fertilized, subject to the placement of mulch or yard waste or otherwise disturbed, except for:
1. Periodic cutting or burning that promotes the health of the setback or to maintain the proposed natural community;
2. Removal of trees, limbs, or branches that are dead, diseased, or pose safety hazards;
3. Actions to address disease or invasive species;
4. Mowing for purposes of public safety;
5. Mowing or clearing of trees and shrubs to create an access path no more than 12 feet in width to allow access to the water resource;
6. Temporary disturbance for placement or repair of buried utilities; or
7. Other actions to maintain or improve setback quality, each as approved by the CCWMO.
(b) Pesticides and herbicides may be used in accordance with Minnesota Department of Agriculture rules and guidelines.
(c) Once vegetation is established in a setback, no fill, debris or other material shall be excavated from or placed within a setback except as allowed under § 153.59(B)(4)(a).
(d) Areas of the transition setback that will be disturbed by grading activities during construction, shall be planted according to the following standards:
1. Soils must be decompacted to a depth of 18 inches and organic matter must be incorporated into soils before seeding or planting. Decompaction shall be accomplished solely by incorporation of organic matter within the drip line or critical root zone of trees or within ten feet of underground utilities.
2. Transition setback areas shall be planted with a native seed mix and/or native plantings approved by the CCWMO.
(5) Recording of setback. The setback shall be documented by a declaration or other document approved by the CCWMO or municipality and recorded in the office of the County Recorder before the permit will be issued.
(6) Monumentation. The setback shall be indicated by permanent, free-standing markers at the setback's upland edge. Monumentation shall conform with the guidelines described in § 153.62
.
(7) Maintenance. The setback shall be maintained in accordance with the provisions outlined in the Carver County Water Management Ordinance and BMP guidelines and with any applicable establishment and maintenance plans.
(Ord. 57-2005, passed 1-10-06; Am. Ord. 75-2012, passed 6-26-12; Am. Ord. 83-2016, passed 9-20-16; Am. Ord. 99-2022, passed 6-28-22)